a. 1,724.000 kHz.
c. 1,725.000 kHz.
b. 1,724.575 kHz.
d. 1,726.275 kHz.
11. How is the process of scanning applied to facsimile transmission?
a. Reflections of the light beam cause modulation of the transmitter.
b. A constant-speed drum progresses a uniform amount along a drive shaft with each revolution.
c. A synchronizing signal coordinates drum rotation at both sending and receiving terminals.
d. The received signals control the intensity of a light beam on the receiving drum.
12. Radio waves from a vertical antenna are sometimes received over greater distances than expected. This
results from the fact that a vertical antenna radiates
a. all of the energy along the ground.
b. all of the energy at an angle to ground.
c. some of the energy skyward, with most along the ground.
d. some of the energy along the ground, with most going skyward.
13. Four characteristics of a radio wave in free space are: amplitude, frequency, velocity, and wavelength.
The only characteristic that remains constant is
a. wavelength.
c. frequency.
b. amplitude.
d. free-space velocity.
14. What is the wavelength of a 60-MHz radio signal?
a. 5 meters
c. 50 meters
b. 10 meters
d. 100 meters
15. How do the two radio signals shown in figure 4-3 differ?
a. They have different waveforms.
b. Their velocities are not the same.
c. Their frequencies are not the same.
d. They have been modulated with different intelligence.
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